Amplifying apparatus



July 1, 1941.` G, BARTH l 2,247,983

AMPLIFYING APPARATUS NVENTOR.

July l, 1941. I G. BARTH 2,247,983

AMPLIFYING APPARATUS Filed March 6, 1940 2 Sheets-Sheet 2 I I .s l 43 f3 43 fw 37 37 l-Tg B l-T 9 j INVENTOR.

MM MM ATTORNEY.

Patented July 1, 1941 Y 2,247,983 AMPLIFYING APPARATUS Gustav Barth, Berlin,

Germany,

assignor to Siemens Apparate und Maschinen Gesellschaft mit beschrnkter Haftung, Berlin, Germany, a

corporation of Germany In Germany December 24, 1938 Application March (i, 1940, Serial No. 322,635

12 Claims. '4(Cl. 179-171) This invention relates to amplifying apparatus, and more particularly to means for amplifying anelectric current.

One of the objects of the present invention is to provide novel means which are especially adapted for use in aircraft navigational apparatus for amplifying an electric current.

Another object of theinvention is to provide novel means for governing a movable member, such as a control surface of an aircraft.

A further object is to provide a novel apparatus of the above character which is inexpensive to manufactiue, light in weight, and which occupies a small amount of space.

An additional object is to provide novel current amplifying apparatus which can .be used with direction responsive devices on board aircraft. Y

A` further object is to provide a novel electric current amplifying device which is .adapted for reversibly controlling a movable member by an output current having the same value for an input current having opposite signs.

The above and further vobjects andy novel features will more fully appear from `the detailed description when the same is read in connection with the accompanying drawings. It is to be expressly understood, however, that the drawings are for purposes of illustration only and are not intended as a definition of the limits of the invention, reference for this latter purpose being had to the appended claims.

In the drawings, wherein like reference characters refer to like parts throughout the several views,

Fig. 1 is a schematic illustration of an amplier apparatus necessary for an explanation of the present invention;

Fig. 2 is a diagram of the characteristic curves of the device shown in Fig. 1;

Fig. 3 is a schematic illustration of another ampliner apparatus 'which is employed for the same purpose as the apparatus of Fig. 1;

Fig. i is a schematic illustration of one embodiment of the -present invention;

Fig. 5 is an illustration ofthe characteristic curves of the embodiment of Fig. 4;

Fig. d is a schematic illustration of a second embodiment of the invention; Fig. '7 is a partial schematic illustration of means, which, in combination with part of the embodiment of Fig. 6, comprise a third embodiment of the invention;

Fig. Sis a schematic detail View of a coil circuit which can be employed with the embodiment of Fig. 6; and

Fig. 9 is another detail view of another coil circuit which can be employed with the embodiment of Fig. 6.

The forms of the invention illustrated in the accompanying drawings comprise improvements in the inventions set forth in my copending application, Serial No. 290,968, filed on August 19, 1939, and are constituted, by way of example, by improvements in means for controlling a movable member, such as a control surface of a vehicle, in accordance with a navigational instrument, such as a gyro compass, which can handle small loads only. Two amplifier units, each including a core element of magnetizable material such as Permalloy, are herein employed which are electrically connected with one another and which have a common control member, such as a gyro compass, which governs the flow of current to an input circuit, the latter including one or more input coils upon each of said elements. An output circuit is associated with each of said units, and each of said circuits includes a plurality of output coils through which flows an alternating current. In order that only one of the above core elements be materially eifective at one time, for a purpose to appear later, means are provided for giving an unsymmetrical form tothe characteristic curve of each unit. The latter means comprise a rectier in each of the output circuits and a counter-coupling coil upon each core element. The rectified alternating current in the output circuit of one element is conducted to the counter-coupling coil mounted upon the other element, and means are provided for conducting the rectified current in the remaining output circuit to the counter-coupling coil upon the remaining element.

The apparatus shown in Figs. 1 and 3 is introduced for purposes of illustrating the operating principle of the invention set forth in the above mentioned copending applications. This principle is: based upon the fact that the inductance of suitable Coils upon a magnetic core can be varied by controlling the permeability of the core. Suitable means are provided for controlling this permeability in accordance with a control force of a controlling instrument. In Fig. 1, a core element l0 is employed having similar members` Il and l2, which are of a highly permeable substance, such as iron-nickel alloy. The members Il and I2 are, for example, of a rectangular or closed form. An input circuit is provided for element I0 having an input coil IS, which is common to members II and I2, and which is electrically connected to a control instruinent I, which governs, by suitable means (not shown), a flow of direct current to the coil I3. On the members I! and I2, respectively, are output coils I5 and i3 which comprise portions of an output circuit which is energized by a source of alternating current Il'. Coils i5 and I@ are in series with one another and with a rectiiier IS to which is operatively connected a suitable consuming device, such as an electric servomotcr I9, the latter being operatively associated with a movable member 2S. The motor I9 is preferably controllable by a rotary magnet relay device (not shown). The rectifier I8 transforms the current in the output circuit into a direct ciurent J1 Which controls the servo-motor I9.

The magnitude of an alternating current J2, which ows through coils l5 and I6, is a function of the reactance of these coils. The magnitude of the direct current J1, which controls motor I9, is a function of the magnitude of this alternating current and is dependent upon the reactance of said coils. This reactance, in turn, is a function of the permeability of the core element I which corresponds to the working point of the magnetization characteristic curve or the device.

For reasons of simplicity and clarity, all coils shown in the drawings are assumed as being wound in the same direction. The coils I and I6 are connected with each other in such a manner that the voltages induced thereby in the coil I3 compensate one another.

In operation, an input direct current ie, which flows in the coil I3, creates a constant magnetic flux in the members II and I2, thus displacing the Working point of the magnetization characteristic curve. Coincident with the displacement of the Working point, there occurs a variation of the permeability and therewith a variation of the reactance of coils I5 and I6. The direct current J1, which controls motor I9, is consequently a function of the input current ie.

In the diagram of Fig. 2, there is shown a characteristic curve for a device of this character which illustrates that the output current J1 is a function of the input current ie, the latter current being plotted against J1 in a conventional manner. Starting from a value of the input current 222:0, the output current J1 ascends from a value of zero in approximately a straight line when ie is positive. However, J1 reaches a limit value when the input current has increased a predetermined amount. If the input current ie ows in coil I3 in an opposite direction, that is, when ie becomes negative, the same value for J1 is obtained. Consequently, for a negative ie a corresponding characteristic curve, as shown by the dotted line, is formed upon the opposite side of the vertical axis of the diagram of Fig. 2. Both of the characteristic curves, including the one shown by a full line and the one shown by a dotted line, are completely symmetrical With reference to the axis of ordinates. Consequently, the direction of ie is of no importance in determining the magnitude of J1.

If the consuming device, which is electrically connected to rectifier I8, comprises a conventional rotary magnet, the latter can operate only in one direction because the output direct current J1 can ow in the rotary magnet in one direction only. In other words, the direction of rotation cannot be aiected. However, it is possible to reverse the direction of rotation of such LLI a magnet and hence to reversibly control the direction of rotation of a member, such as a servomotor I9, by means of the apparatus shown in Fig. 3. The structure shown in this Figure is analogous to that appearing in Fig. 1, with the exception that a regenerator coil 2| is mounted upon the core element I0 in a manner similar to that of coil I3. Through the coil 2l there Iiows a direct current which is obtained from a rectifier 22, the latter being electrically connected to the output circuit. The effect of the direct current iiowing in coil 2I is to displace the axis of the ordinates. Coil 2| thus accomplishes a premagnetizati'on which, in Fig. 3, is indicated symbolically by the arrow 23. The direct current owing in coil 2I is preferably of such a value that when ie equals zero, the axis of the ordinates intersects the full line curve at approximately the mid-point thereof. The intersection is shown at point P of Fig. 2. The output current corresponding to this point of intersection is J p.

A rotary magnet 24 is operatively connected to rectifier I8 of Fig. 3, a coil 25 which acts upon a movable pointer, or arm 26, being electrically connected to the rectifier. As above mentioned, when ie=0 the current Jp iows in the circuit connected to rectifier I8. Consequently, a torque will be continually exerted against the pointer 26. In order` to maintain arm 2B in a predetermined central position, a counter torque must be exerted thereupon which, in the structure o! Fig. 3, is exerted by a coil 21 which is electrically connected to a suitable source of direct current for this purpose.

In operation, when the current ie flows through the coil I3 in Fig. 3, a constant magnetic iiux which is produced therein is indicated either by arrow 28 or 28a. This flux either intensifies or weakens 4the premagnetization which is produced by the coil 2I and thereby causes either a rise or a drop of the current J in the coil 25. Therefore, the torque which is exerted upon arm 26 of the rotary magnet reverses its direction in response to a change in direction of the input current ie.

The apparatus shown in Fig. 3, however, has a number of defects. For the displacement of the zero point of the characteristic curve there is required a permanent and a constant premagnetization which makes it necessary to conduct a vconstant direct current to the coil 2l. This requires either a constant current source or as the premagnetization current is derived from the current source II, as shown in Fig. 3, there must be provided means which will regulate that current source to produce a constant potential or to provide means for compensating for potential fluctuations.

Also, in the zero position" of this device, that is, in a position in which arm 26 is at a predetermined central location. there ows in the amplier system an alternating current and also the direct current Jp which corresponds to the working point P on the characteristic curve. This current represents a constant loss of energy.

An amount of energy which corresponds to the aforementioned loss must be supplied by the current source which is connected to coil 21, in order to provide the proper compensation torque or turning moment. Means (not shown) should be provided for controlling the torque exerted by coil 21 to compensate for voltage changes in current source II if the resultant torque in the central position of arm 26 is to be zero.

The consuming apparatus 24 must therefore be much larger and heavier than it would be if no compensating torque were required. In order to reduce the weight and power losses of devices having a single amplifier unit, such as that of Fig. 3, a double unit apparatus is provided, each unit being partially analogous to that shown in Fig. 1. The units are electrically associated in such a manner that only one thereof is materially activ-e or effective at any one time. One unit is adapted for moving a consuming device, such as a relay, in one di-rection, whereas the other unit is adapted for moving the device in an opposite direction.

One embodiment of the present invention which :avoids the above defects by employing a double unit amplifier' is illustrated schematically in Fig. 4 in which the members I0, I0', II, II', I2, I2', I3, I3', I5, I5', I6 and I6' correspond to the `same members shown in Fig. 1. The output circuits of both units are fed preferably from the same alternating current source I'I'. The direct current ie for energizing the input circuits of units I and II is controlled by an instrument, such as a gyro compass 29. The coils I3, I3' of .the input circuits are in this embodiment connected in series.

For a purpose to appear hereinafter, a countercoupling coil 33 is mounted upon the core element of unit I in a manner analogous to input coil I3.

A counter-coupling coil is mounted in a similar manner upon core element II. The coils 30 and 30' are respectively energized by currents Ji and J3. of a rectifier IB' in the output circuit of unit II,

and the latter current is obtained from rectifier I8 in the output circuit of unit I. Leads 3|, 32 interconnect rectifier I8' and coil 30, and leads 33, 34 interconnect rectifier I8 and coil 30'.

A suitable consumer device is -operatively connected to the apparatus comprising, for example, a relay analogous to member 24 of Fig. 3. Relay 35 is provided with a movable arm 36 which is governed by opposing coils 31 and 38. The latter coils are respectively connected in the leads 34 and 32. The terminals of lthe apparatus to which member 35 is connected comprise terminals d and d on opposite sides of coil 31, and terminals b and c on opposite `sides of coilA 38. A second stage of an amplier device can be connected to these terminals in place of member 35 in a manner to appear later. Movable arm 33 can control, for example, the direction :of a current to a servo-motor (n-ot shown) which can be operatively connected to a movable member, such as a control surface of an aircraft (also not shown).

The direction of direct currents Ja, J4 are determined by the direction of rectiiiers I8, I8', respectively, for example, as indicated by arrows in leads 34 and 32. If the input current ie controlled by instrument 29 iiows inthe direction indicated by a single arrow 39 in the leads of the input circuit, there are created by means of coils I3, I3' constant magnetic fluxes in members I0 and I il', which are indicated diagrammatically by arrows 40, 42', respectively. The currents in the counter-coupling coils 30, 30 create fluxes which are respectively indicated by arrows 4I, 4 I

When the current i@ flows in the above mentioned direction, the constant fluxes resulting from the currents is and J4 will add in `unit I, that is, the iiuXes of coils I3 and 3U will act in conjunction with one another in this unit, where- The former current is obtained by means as the fluxes of coils I3' and 30' will subtract or act in opposition to one another in unit II.

If the direction of current ie is reversed, as indicated by arrow 42 in the input circuit, the magnetic fluxes will subtract in unit I, and add in unit II. Thus, the eiiect of the countercoupling coil is substantially to neutralize the electrical influence of an input coil of one unit and to intensify this iniiuence in the other unit when the input current flows in a given direction.

In operation, for a zero value of ie certain alternating 4currents ilow in the output coils of the two units because the reactances or impedances of these coil-s have fina-l or limit values. The rectied alternating current flowing in each output circuit displaces the working point on the magnetization curve of the opposite unit by creating :a flux as above mentioned in a countercoupling coil upon said opposite unit (Fig. 5). The magnetization curve for each unit is shown in Fig. 5 under this condition, from which it is seen that corresponding to the displacement of the working point of each curve there exists a value of J3 and J 4 when ie=0 which is somewhat larger than if .the coils 33, 30' were omitted. If lie increases in a positive direction, for example, as shown, by arrow 39 the current Ja of unit I rises. However, in unit II when ie increases, current J4 drops at rst to a minimum value which occurs, in the present form, when the magnetic fluxes created in coils I3' and 3D' compensa-te one another. From this point the input current ie creates a constant magnetic iiux in element I il', the strength of which is changed by the effect of the increasing J3 in coil 3U'. Consequently, J4 rises slowly with the increasing The characteristic curve of each unit is completely unsymmetrical with respect to the axis of ordinates contrary .to the symmetry of the characteristic curve shown in Fig. 2. The lack of symmetry creates a condition wherein :for positive Values of the input current ie, starting from a zero Value thereof, only the current J3 of unit I is materially effective upon the rotary magnet 35, whereas, due .to the counter-coupling of the Itwo units, the current J4 remains below the value 'thereof which exists when 112:0. Consequently, J4 is substantially ineffective when z`e=0 and Ja urges arm 36, for example, to the left. The opposite condition prevails when ze is negative.

In the form shown in Fig. 4, the units I and II are similar and are constituted by the same substance. Consequently, as in Fig. 5, the characteristic curve of each unit is analogous to that of the other and the curves intersect one another at the axis of ordinates, thereby causing relay 35 to respond symmetrically for equal and opposite values of ie. This is a special advantage as compared with the embodiment of Fig. 3 because, as shown in Fig. 2, it is impossible to have a characteristic curve having the same form on opposite sides of the Working point P.

In order to control the slope and shape of the characteristic curve of each unit, it is possible to employ an additional coil or coils in association with each of the core elements of these units. An embodiment wherein an added coil is mounted upon each element is illustrated in Fig. 6. This embodiment is similar in all respects to that of Fig. 4 with the exception (l) that input coils I3, I3 are connected in parallel instead of in series, and (2) that regenerator coils 43 and 43 are respectively mounted upon core elements I0 and I3' in a manner similar to input coils i3 and i3. Coil 43 is connected in lead 33 and is energized by current from rectifier I8 in the output circuit of its own unit. Coil 43 is connected in lead 3l and is analogously energized by current from rectifier I8. In the forni shown in Fig. 6, the fluxes of the regenerator coils 43, 43 support the action of the iiuxes of countercoupling coils 30, 35', respectively.

The regenerator and counter-coupling coils of Fig. 6 are in series; however, these coils can be connected in parallel as shown in Figs. 8 and 9, each of which illustrates said coils for one unit only. The circuits of Figs. 8 and 9 are similar with the exception that in the former, coil 31 is interposed between one extremity of each of coils 43 and 30', whereas in the latter coil 31 is between coil 43 and rectiiier I 8.

The amplifier apparatus above described in connection with Fig. 6 can be employed as an input stage of a multi-stage amplifier provided member 35 is disconnected therefrom at terminals a, b, c, d and, for example, a second amplier stage is connected thereto. A second ampliiier stage is illustrated in Fig. '1 which comprises units I and II', the former having input coils 44, 45, the latter having input coils 4B, 41. In the form shown, coils 44 and 46 are in series in a lead 48 connected at terminals a and d. Coils 45 and 41 are in series in a lead 49. The two units I and II' are analogous to units I and II, with the exception of the input coils. Portions of units I and II have been omitted for clarity.

In operation, the rectied current provided by rectifier I8 flows through coils 44, 46, and the rectified current from rectifier I8 is conducted through coils 45, 41. Magnetic fluxes are created by these currents which are indicated diagrammatically in Fig. 7 by arrows 5D, 5I for coils 44, 45, and by arrows 52, 53 for coils 45, 41, respectively. positely directed as are those of the second pair. When z`e=0 the currents in the second stage input coils are of equal values; therefore, the uxes of coils 44, 45 compensate one another as do those of coils 4B, 41. Consequently, the amplifier apparatus is in an inoperative condition. However, if a positive or negative ie flows in the input coils of the first amplifier stage, then the Iiuxes directed to the right, as indicated by arrows 50, 52, or the fluxes directed to the left, as indicated b-y arrows 5l, 53, will predominate and, for eX- arnple, a relay (not shown) which is connected to the second amplifier stage, together with said second stage will become operative in a manner similar to that above described.

There is thus provided novel means for amplifying an electric current. The means are extremely light in weight, inexpensive to manufacture, and are therefore well adapted for use aboard vehicles, such as aircraft. The apparatus enables instruments such as the above mentioned compass, which can exert only a very small torque, to govern accurately the control surface of an aircraft. Moreover, the device is highly eicient in that the two amplifier units operate substantially at that point of the characteristic curve at which the energy consumption of the device is lowest when ie=0. 'Ihis eliminates the diiiiculties which are encountered in stabilizing the working point of the device on the characteristic curves of the device, for example, against voltage fluctuations. Also, the consuming device,

such as the relay 35, requires no means for torque compensation as is necessary in the embodiment of Fig. 3. Also, by selecting the electrical qualities The arrows of the iirst pair are op- CII of the counter-coupling coils, it is possible to correct irregularities in the device resulting from mass production, due7 for example, to lack of uniformity of the magnetic qualities of the core elements.

Although only three embodiments of the present invention have been illustrated and described in detail, it is to be expressly understood that the invention is not limited thereto. Various changes in the design and arrangement of the parts can be made without departing from the spirit and scope of the invention as the same will now be understood by those skilled in the art. For a definition of the limits of the invention, reference will be had primarily to the appended claims.

What is claimed is:

l. Amagnetic amplifier comprising a iirst magnetizable core carrying a first winding and a second winding connected in series opposed relation, a second magnetizable core carrying a first wind ing and a second winding in series opposed relation, a source of alternating current connected to energize the iirst and second windings on each of said two cores, a direct current input circuit including a third winding on said first core and a third winding on said second core, the third winding of one core being connected in aiding relation with the third winding of the other core, a fourth winding on said first core and a fourth winding on said second core, said fourth windings being wound in opposed relation, a pair of rectiiiers, a Iirst output circuit including the rst and second windings of the first core, the fourth winding of the second core and one of said rectiiiers, whereby the alternating current in the first and second windings of the iirst core is rectified and then caused to flow as a direct current in the fourth winding of the second core, a second output circuit including the nrst and second windings of the second core, the fourth winding of the first core and the other of said rectiiiers, whereby the alternating current in the first and second windings of the second core is rectiiied and then caused to flow in the fourth winding of the first core, and a consuming device connected to be differentially energized by the two output circuits.

2. A magnetic amplifier comprising a first magnetizable core carrying a rst winding and a second winding connected in series opposed relation, a second magnetzable core carrying a nist winding and a second winding in series opposed relation, a source of alternating current connected to energize the first and second windings on each of said two cores, a direct current input circuit including a third winding on said iirst core and a third winding on said second core, said third windings being connected in series aiding relation, a fourth winding on said first core and a fourth winding on said second core, said fourth windings being wound in opposed relation, a pair of rectifiers, a first output circuit including the first and second windings of the iirst core, the fourth winding of the second core and one of said rectifiers, whereby the alternating current in the first and second windings of the first core is rectified and then caused to flow in the fourth winding of the second core, a second output circuit including the iirst and second windings of the second core, the fourth winding of the first core and the other of said rectiers, whereby the alternating current in the iirst and second windings of the second core is rectified and then caused to iiow in the fourth winding of the first core, and a consuming device connected to be differentially energized by the two output circuits.

3. A magnetic amplifier comprising a magnetizable core carrying a first winding and a second winding connected in series opposed relation, a second magnetizable core carrying a first winding and a second Winding in series opposed ree lation, a source of alternating current connected to energize the first and second windings on each of said two cores, a direct current input circuit including a third winding on said first core and a third winding on said second core, said third windings being connected in parallel and in aiding relation, a fourth winding on said first core and a fourth winding on said second core, said fourthy windings being wound in opposed relation, a pair of rectifiers, a first output circuit including the first and second windings of the first core, the fourth winding of the second core and one of said rectifiers, whereby the alternating current in the first and second windings of the first core is rectified and then caused to fiow in the fourth winding of the second core, a second output circuit including the first and second windings of the second core, the fourth winding of the first tcore and the other of said rectifiers whereby the alternating current in the first and second windings of the second core is rectified and then caused toi iiow in the fourth winding of rthe first core, and a consuming device connected to be differentially energized by the two output circuits.

4. A magnetic amplifier comprising a first magnetizable core lcarrying a first winding and a second winding connected in series opposed relation, a second magnetizable core carrying a first winding and a second winding in series opposed relation, a source of alternating current connected to energize the first and second windings on each of said two cores, a direct current input circuit including a third winding on said first core and a third winding' on said second core, the Ithird winding of one core being connected in aiding relation with the third winding of the other core, a fourth winding on said first core and a fourth winding on said second core, said fourth windings being wound in opposed relation, a pair of rectifiers, a first output circuit including the first and second windings of the first core, the fourth winding of the second core and one of said rectifiers, whereby the alternating current in the first and second windings of the first core is rectified and then caused to flow as a direct current in the fourth winding of the second core, a second output circuit including the rst and second windings ofthe second core. the fourth winding of the first core and the other of said rectifiers, whereby the alternating current in the first and second windings of the second'core is rectified and then caused to now .as a direct current in the fourth winding of the first core, and a consuming device having two windings-one of which is connected to be energized by one output circuit and the other of which is connected to be energized by the other output circuit.

5. A magnetic amplifier comprising a first magnetizable core carrying a first winding and a second winding connected in series opposed relation, a second magnetizable core carrying a first rwinding and a second winding in series opposed relation, a source of alternating current connected to energize the first and second windings on each of said two cores, a direct current input circuit including a third winding von said first coreandy athird winding on said secon-d core, said third windings being connected in series aiding relation, a fourth winding on said first core and a fourth winding on said second core, said fourth windings being wound in opposed relation, apair of rectiers, a first output circuit including the first and second windings of the first core, the fourth winding of the second core and one of lsaid rectifiers, whereby the alternating current in the first and second windings of the first core is rectified and then caused to fiow in the fourth winding of the second core,

a second-output circuit including the first and* second windings of the second core, the fourth winding of thel first core and the other of said rectifiers, whereby the alternating current in the first and second windings of the second core is rectified and then caused to flowv in the fourth winding of the first core, and a consuming ldevice having two windings one of which is connected to be energized by one output circuit and the other of which is connected to be energized by the other output circuit.

6. A magnetic amplifier comprising a magnet izable core carrying a, first winding and a second winding connected in series opposed relation7 a second magnetizablek core carrying a first winding and a second winding in series opposed relation, a source of alternating current connected to energize the first Iand second windings on each of said two cores,la :direct current input circuit including a third Winding on said first core and a third winding on said second core, said third windings bei-ng connected in parallel and in aiding relation, a fourth winding on saidy first core anda fourth winding on said second core, said fourth windings being wound in opposed relation, a pair of rectifiers, a first output circuit including the first and second windings of the first core, the fourthfwinding ofthe second core and one of said rectiflers, whereby the alternating current in the first and second windings of the first core is rectified and then caused to fiow in the fourth winding of the second core, a second output circuit including the firstand second windings4 of the second core. the fourth winding ofthe first-core and the other of said rectifiers whereby the alternating current in. the first and second windings of the secondcore is rectified and then caused tof iicw in the fourth winding of the'first core, anda consuming device having two windings one of which is connected. to be energized by one output circuit and the other of which is connected tobe energized by the other output circuit. l f

'7.- Amagnetioampliiier comprising a first magnetizpable core carrying a first winding and asecond winding connected in series ropposed relation, a second magnetizable. core carrying a first winding and a second winding in series opposed relation, a source of alternating current-connected to s energize the first and second windings on each of said two cores, a direct current input circuit including a thirdv winding on said first core vanda `third winding von said second core, the third posed relation, a pair of rectifiers, a first output circuit including the first, second and fifth windings of the first core, the fourth winding of the second core and one of said rectifiers, whereby the alternating current in the first and second windings of the first core is rectified and then caused to flow as a direct current in the fourth winding of the second core and in the fifth winding of the first core, a second output circuit including the first, second and fifth windings of the second core, the fourth winding of the first core and the other of said rectifiers, whereby the alternating current in the first and second windings of the second core is rectified and then caused to flow as a direct current in the fourth winding of the first core and in the fifth winding of the second core, and a consuming device connected to be differentially energized by the two output circuits.

8. A magnetic amplifier comprising a first magnetizable core carrying a first winding and a second winding connected in series opposed relation, a second magnetizable core carrying a first winding and a second winding in series opposed relation, a source of alternating current connected to energize the first and second windings on each of said two cores, a direct current input circuit including a third winding on said first core and a third winding on said second core, the third winding of one core being connected in series aiding relation with the third winding of the other core, a fourth winding on said first core and a fourth winding on said second core, said fourth windings being wound in opposed relation, a fifth winding on said first-l core and a fifth winding on said second core, said fifth windings being wound in opposed relation, a pair of rectifiers, a first output circuit including the first, second and fifth windings of the first core, the fourth Winding of the second core and one of said rectifiers, whereby the alternating current in the first and second windings of the first core is rectified and then caused to flow as a direct current in the fourth winding of the second core and in the fifth winding of the first core, a second output circuit including the first, second and fifth windings of the second core, the fourth winding of the first core and the other of said rectifiers, whereby the alternating current in the first and second windings of the second core is rectified and then caused to fiow as a direct current in the fourth winding of the first core and in the fifth winding of the second core, and a consuming device connected to be differentially energized by the two output circuits.

9. A magnetic amplifier comprising a first magnetizable core carrying a first winding and a second winding connected in series opposed relation, a second magnetizable core carrying a first Winding and a second winding in series opposed relation. a source of alternating current connected to energize the first and second windings on each of said two cores, a direct current input circuit including a third winding on said first core and a third winding on said second core, the third winding of one core being connected in parallel aiding relation with the third winding of the other core, a fourth winding on said first core and a fourth winding on said second core, said fourth windings being wound in opposed relation, a fifth winding on said first core and a fifth winding on said second core, said fifth windings being wound in opposed relation, a pair of rectifiers, a first output circuit including the first, second and fifth windings of the first core, the fourth Winding of the second core and one of said rectifiers, whereby the alternating current in the first and second windings of the first core is rectified and then caused to flow as a direct current in the fourth winding of the second core and in the fifth Winding of the first core, a second output circuit fncluding the first, second and fifth windings of the second core, the fourth winding of the first core and the other of said rectifiers, whereby the alternating current in the first and second windings of the second core is rectified and then caused to fiow as a direct current in the fourth winding of the first core and in the fifth winding of the second core, and a consuming device connected to be differentially energized by the two output circuits.

10. A magnetic amplifier comprising a first magnetizable core carrying a first winding and a second winding connected in series opposed relation, a second magnetizable core carrying a first winding and a second winding in series opposed relation, a source of alternating current connected to energize the rst and second windings on each of said two cores, a direct current input circuit including a third winding on said first core and a third winding on said second core, the third winding of one core being connected in aiding relation with the third winding of the other core, a fourth winding on said first core and a fourth winding on said second core, said fourth windings being wound in opposed relation, a fifth winding on said first core and a fifth winding on said second core, said fifth windings being wound in opposed relation, a pair of rectifiers, a first output circuit including the first, second and fth windings of the first core, the fourth winding of the second core and one of said rectifiers, whereby the alternating current in the first and second windings of the first core is rectified and then caused to flow as a direct current in the fourth winding of the second core and in the fifth winding of the first core, a second output rcircuit including the first, second and fifth windings of the second core, the fourth winding of the first core and the other of said rectifiers, whereby the alternating current in the first and second windings of the second core is rectified and then caused to fiow as a direct current in the fourth winding of the first core and in the fifth winding of the second core, and a consuming device having two windings one of which is `connected to be energized by one output circuit and the other of which is connected to be energized by the other output circuit.

l1. A magnetic amplifier comprising a first magnetizable core carrying a first winding and a second winding connected in series opposed relation, a second magnetizable core carrying a first winding and a second winding in series opposed relation, a source of alternating current connected to energize the first and second Windings on each of said two cores, a direct current input circuit including a third winding on said first core and a third winding on said second core, the third winding of one core being connected in series aiding relation with the third winding of the other core, a fourth winding on said first core and a fourth winding on said second core, said fourth windings being wound in opposed relation, a fifth winding on said first core and a fth winding on said second core, said fifth windings being wound in opposed relation, a pair of rectifiers, a first output circuit including the first, second and fifth windings of the first core, the fourth winding of the second core and one of said rectifiers, whereby the alternating current in the first and second windings of the first core is rectified and then caused to fiow as a direct current in the fourth winding of the second core and in the fifth winding of the first core, a second output circuit including the first, second and fifth windings of the second core, the fourth winding of the first core and the other of said rectifiers, whereby the alternating current in the first and second windings of the second core is rectified and then caused to flow as a direct current in the fourth winding of the first core and in the fifth winding of the second core, and a consuming device having two windings one of which is connected to be energized by one output circuit and the other of which is connected to be energized by the other output circuit.

12. A magnetic amplifier comprising a first magnetizable core carrying a first winding and a second winding connected in series opposed relation, a second magnetizable core carrying a first winding and a second winding in series opposed relation, a source of alternating current connected to energize the first and second windf ings on each of said two cores, a direct current input circuit including a third winding on said first core and a third winding on said second core, the third winding of one core being connected in parallel aiding relation with the third winding of the other core, a fourth winding on said first core and a fourth winding on said second core, said fourth windings being wound in opposed relation, a fifth winding on said first core and a fth winding on said second core, said fifth windings being wound in opposed relation, a pair of rectiners, a first output circuit including the first, second and fifth windings of the first core, the fourth winding of the second core and one of said rectifiers, whereby the alternating current in the first and second windings of the first core is rectified and then caused to flow as a direct current in the fourth winding of the second core and in the fifth winding of the first core, a second output circuit including the first, second and fifth windings of the second core, the fourth winding of the first core and the other of said rectifiers, whereby the alternating current in the first and second windings of the second core is rectified and then caused to flow as a direct current in the fourth winding of the first core and in the fth winding of the second core, and a consuming device having two windings one of which is connected to be energized by one output circuit and the other of which is connected to be energized by the other output circuit.

GUSTAV BARTH. 

